Conventionally, the hybrid vehicle utilizing both of an internal combustion engine and a motor as its power source for driving the vehicle is equipped with an apparatus that reduces the fuel consumption of the engine by (a) planning a schedule of driving the engine and the motor according to the route condition of a guidance route extending from the departure place to the destination and (b) controlling the engine and the motor according to the schedule of driving of the engine and the motor. Such an apparatus is disclosed, for example, in Japanese patent documents JP-A-2000-333305 (now available as U.S. Pat. No. 6,314,347) and JP-A-2001-183150.
According to the disclosure in those patent documents, plan section setting for setting certain road sections as a travel plan of the vehicle is performed in the following fashion. That is, when a guidance route between the departure place and the destination is searched for, the searched route is set as a “plan section” of the travel plan of the vehicle. When the vehicle is used for commuting or the like, the frequently-traveled route is recorded by the navigation apparatus in association with the time of actual travel (i.e., commuting), and the recorded travel route is used as the plan section of the travel plan of the vehicle's travel in the frequently-traveled time slot, assuming that the vehicle will follow the frequently-traveled route of the recorded travel.
However, in the above-described fashion, an expected travel plan intended by an occupant of the vehicle is not necessarily reflected to the plan section of the travel plan set by the apparatus. Further, once set, the plan section in the created travel plan cannot be changed/modified by the occupant. As a result, the vehicle's travel controlled by the conventional planning apparatus could not have achieved, in some cases, an expected target value of fuel consumption, due to the plan section of the travel plan that is solely made up by the planning apparatus, but not intended by the occupant.